The present invention relates to the field of electromechanical or electronic keys and locks for preventing access to a given place or for preventing a determined apparatus from being put into operation, for example a rack or cabinet of electronics.
Over the last few years, locks have been developed that associate mechanical encoding, e.g. implemented in the form of notches, with electronic encoding transmitted between the key and the lock. Patent application EP 0 277 432 shows an example of such an electromechanical lock in which the key comprises not only mechanical encoding for unlocking the lock, but also an electronic circuit which acts, on insertion of the key, to transmit a preprogrammed identity code to the lock. The key is powered from the lock which is itself powered from an external source. Similarly, application FR 2 561 292 discloses an electronic key capable of being used with an electromechanical lock and having both notches for mechanical encoding and an electronic microprocessor circuit powered by electricity taken from a rechargeable battery placed directly in the key.
Nevertheless, both the above locks suffer from a major defect that results from the fact that the type of cylinder used is particularly complex to make and is thus very expensive. In that type of lock, it is the difficulty of copying the mechanical profile of the cylinder which guarantees maximum security and not the additional electronic encoding. As a result, if the key is lost, then it is necessary to replace the cylinder whether or not it is associated with an electronic circuit.
Also, in application EP 0 388 997, its Proprietor proposes a lock which is an entirely electronic lock and which is unlocked solely by a match between the identity codes of the key and of the lock.
That type of electronically-locked lock nevertheless also suffers from certain drawbacks, in particular with respect to its power supply which is generally obtained from an external source or from a rechargeable battery. Unfortunately, such an external source is not always available, and using a battery placed inside the lock, in the key, or in both of them simultaneously, suffers from serious difficulties of recharging and of reliability in operation.
An of the present invention is to mitigate the above-specified drawbacks by proposing an electronic lock and key assembly that is entirely self-contained, requiring no independent power supply, whether external or in the form of one or more batteries that can be recharged by means of an external device. Another object of the invention is to provide a lock cylinder and a key each of which is relatively simple to make and low in cost, and which guarantee that the system is completely secure.
These objects are achieved by an electronic key comprising, mounted in a key body, a key shank for insertion into a corresponding housing of a lock cylinder for the purpose of unlocking it, the cylinder having a stator portion and a rotor portion secured to a tongue, and including first mechanical means and first electronic means, and the key including second mechanical means and second electronic means for co-operating with the corresponding first means of the cylinder when the key is fully inserted in the cylinder and for causing the lock to be unlocked when an identity code of the key and a corresponding code of the lock match, the key being characterized in that the electronic means of the key are powered from self-contained power generator means actuated merely by displacing the key shank in the body of the key.
By means of this particular structure, the electronic means of the key for interchanging and verifying identity codes and possibly also for controlling unlocking of the lock can be powered by a single module actuated solely by moving the shank of the key and independently of any external power supply device.
In a preferred embodiment, the said power generator means is connected via a power link to a rectifier and storage means which generates a DC power supply voltage from AC signals delivered by the power generator means, said rectifier and storage means itself being connected to processor means which, via a communications link connecting it to the power generator means, serves to interchange the data required for unlocking the cylinder.
Advantageously, the power link and the communications link constitute a single link at the power generator means, and the second electronic means then include multiplexer/demultiplexer means for connecting the power generator means both to the rectifier and storage means and to the processor means.
Preferably, the second electronic means further include communications interface means disposed between the processor means and the power generator means for matching and filtering the signals delivered at the output of the processor means.
In a first preferred variant, the rectifier and storage means is also connected to the power generator means so as also to power the cylinder of the lock when the key is inserted in the lock. In this way, the cylinder can operate in self-contained manner without relying on any internal power supply (battery or mains, for example).
In a first example, the power generator means include at least one piezoelectric element designed to generate electric charge from successive bending movements generated by the displacement of the shank of the key. Advantageously, the piezoelectric element is constituted by a single piezoelectric plate embedded at one of its two ends in the body of the key and which can either have a serrated profile designed to co-operate with at least one contact tip of a piezoelectric element of the cylinder while the key is being inserted into the cylinder, or else the end of said piezoelectric plate that is left free has a contact tip and is designed to co-operate with a serrated profile of the key shank during extraction/retraction of the shank out from or into the body of the key.
The key shank may also have an additional piezoelectric element connected to the processor means and designed to interchange data between the key and the cylinder of the lock after the key shank has been inserted in the cylinder.
The key shank may further include at least one contact area connected to the processor means and designed to interchange data between the key and the cylinder of the lock after the key shank has been inserted in the cylinder. Advantageously, the contact area is also connected to the output of the rectifier and storage means to enable the cylinder to be powered from the lock after the key shank has been inserted in the cylinder.
In a particular embodiment of the key, said key shank may be of cruciform shape.
In a second preferred variant, the power generator means comprise firstly a magnetized shank constituting a magnetic core, and secondly a plurality of coils connected in a ring, and separated by walls of material having high magnetic permeability, and contained in a body which is itself made of a material having high magnetic permeability and forming a sheath for said magnetized shank, an ejection system, e.g. using a spring being provided to extract/retract said shank from and into its sheath.
Advantageously, the magnetized shank has a plurality of bipolar annular magnets that are regularly separated by walls of material having high magnetic permeability, the distances between said walls being determined in such a manner as to correspond exactly firstly with the differences between the corresponding walls of the sheath-forming body of the key, and secondly with the walls of said tube of the cylinder.
The bipolar annular magnets have polarities that are determined in such a manner that two adjacent magnets repel each other, with the north/south axes of the magnets being parallel to the longitudinal axis of the shank.
The magnetized shank further includes a wall of material having high magnetic permeability, such as soft iron, and for the purpose, on said wall coming into contact with an external magnetic separation wall of the sheath-forming body of the key, of closing the magnetic circuit when the key is fully inserted into the cylinder.
Preferably, there are four of said coils, with the winding directions of two adjacent coils of said four coils being opposite to the winding direction of the other two coils. The four coils have two distinct electrical contact terminals via which there are respectively provided the power link for powering the second electronic means of the key, and the communications link for interchanging data with the cylinder of the lock.
The invention also provides a lock designed to receive the above-described electronic key and in which the cylinder has at least one power generator means that is actuated during or at the end of insertion of the key so as to power the first electronic means of the cylinder.
In a first advantageous variant, the power generator means also serve to provide coupling between the key and the cylinder of the lock, to enable data, in particular identity codes, to be interchanged between the cylinder and the key after the shank of the key has been inserted in the cylinder.
In a second advantageous variant, the power generator means also makes it possible to cause an element for blocking the tongue to be displaced so as to unlock the lock.
The power generator means is connected via a power link to rectifier and storage means which generate a DC power supply voltage from alternating signals delivered by the power generator means, said rectifier and storage means itself being connected to processor means which, via a communications link connecting it to the power generator means, serves to interchange data required for unlocking the cylinder of the lock, said processor means also serving to drive control means which deliver a control pulse to the power generator means via the communications link, said pulse being of determined duration that is sufficient to release the element for blocking the tongue, thereby unlocking the lock.
Preferably, the first electronic means of the cylinder further include switching means enabling the power generator means to be connected via its communications link both to the processor means and to the control means.
In a first preferred variant, the power generator means of the cylinder comprise at least one piezoelectric element having electrical contact terminals with successive bending movements thereof during insertion of the key generating electric charge at the contact terminals thereof.
The piezoelectric element may be constituted by a single piezoelectric plate embedded at one of its two ends in the rotor portion of the cylinder or by a bimorph whose central portion is embedded in the rotor portion of the cylinder. Each free end of the piezoelectric element has at least one contact tip designed to co-operate with the shank of the key and at least one blocking element designed, in a rest position, to prevent any rotation of the tongue relative to the stator portion of the cylinder.
In a second preferred variant, the power generator means of the cylinder is mounted around the housing, at the inlet to the cylinder, and comprises a tube of high magnetic permeability material, such as soft iron, containing a plurality of coils connected in a ring and separated by regularly spaced walls of material having high magnetic permeability, said coils being designed to co-operate firstly with a magnetized shank forming a magnetic core and carried by the key, and secondly with a key-expelling piston suitable for sliding in the housing and provided with said elements for blocking the tongue.
Preferably, there are four of said coils, with the winding direction of two adjacent coils in said four coils being opposite to the winding direction of the other two coils, and the four coils have two distinct electrical contact terminals via which there are provided respectively a power link for powering the first electronic means, and a communications link for interchanging data and for actuating the blocking element.
In an advantageous example, the tongue comprises firstly a cylindrical body and secondly a fin extending radially from said body, the body having an opening for receiving two hollow annular pieces made of a material of high magnetic permeability and placed one against the other while leaving between them an empty disk-shaped space, the inside dimensions of said pieces corresponding to the outside dimensions of the housing, and each inside wall of the annular pieces in contact with said empty space includes a blocking slot designed to receive said blocking element. The fin includes centering means, e.g. formed by a ball-and-spring assembly, designed to cooperate with corresponding means of the stator portion of the cylinder, e.g. with cavities for receiving the balls.
The key-expelling piston has a central core of material having high magnetic permeability, and at each of the two ends of which there is mounted, about a respective axis, said blocking element formed by a slightly magnetized rotary blade, said blocking blade being pivotable to come into one of said locking slots of the tongue when the power generator means is actuated. The central core is covered in a non-magnetic material and terminated at both ends by respective mechanical interface elements designed to co-operate with the mechanical interface means of the key to transmit the rotary couple.
The present invention also relates to a locking system provided with an electronic key and an associated lock.